There is known a driving circuit of a semiconductor element having a feedback circuit (refer to Patent Document 1, for example). In the feedback circuit, a cathode of a diode is connected to a gate of a semiconductor element, an anode of the diode is connected to a source of the semiconductor element, and a resistor is inserted to be connected between the gate and the cathode or between the source and the anode.
Further, there is known a normally-off composite semiconductor device performing an active oscillation control (refer to Patent Document 2, for example). There is provided a low-voltage device which forms the normally-off composite semiconductor device by being cascode-connected to a normally-on III-nitride power transistor. The low-voltage device has a reduced output resistance to cause a gain of the normally-off composite semiconductor device to be about 10000 or less.
Patent Document 1: Japanese Laid-open Patent Publication No. 2009-253699
Patent Document 2: Japanese Laid-open Patent Publication No. 2012-199547
The above-described feedback circuit can reduce a switching noise to make a driving circuit system of a switching element to be stably operated. However, when the feedback circuit is provided, a switching speed of the semiconductor element is sometimes lowered.